Back rest



1936- A. M. SCHOENHOFF I 2,059,493

BACK REST Filed 001:. 11, 1953 5 Sheets-Sheet 2 I N VE/V TO/f.

Nov. 3, 1936. A. M. SCHOENH'OFF BACK REST Filed Oct. 11, 1933 3 Sheets-Sheet 3 I. 4917 I: I

Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to folding back rests for seats.

It is an object of the present invention to provide a novel and improved portable folding back rest of cheap and simple construction, which can be collapsed and extended with great ease and can be applied to various types of seats without difficulty.

More particularly, it is an object of the invention to provide a folding back rest, which can be extended for use on seats of stadiums, fishing boats and elsewhere and which can be collapsed into small compass so that the back rest can be carried without difficulty.

Another object is to provide such a back rest which will hold its position on a seat without loosening therefrom after it has been applied.

The objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the various views, and, in which,

Fig. 1 is a view in side elevation showing an embodiment of the invention applied ready for use on a comparatively thin seat, the seat being shown in vertical section;

Fig. 2 is a similar view of the front portion of the same device applied for use on a comparatively thick seat;

Fig. 3 is a view in rear elevation of the back rest illustrated in Figs. 1 and 2 in extended condition;

Fig. 4 is a view in rear elevation of the same back rest illustrated in collapsed condition;

Fig. 5 is a view in side elevation of the same back rest in collapsed condition;

Fig. 6 is a view in side elevation illustrating a second embodiment of the invention in applied position ready for use on a concrete seat;

Fig. 7 is a plan View looking down on the forward portions of one of the side bars of the seat shown in Fig. 6; and

Fig. 8 is a horizontal section taken on the line 8-8 of Fig. 6, as indicated by the arrows.

Referring first to the embodiment of the invention illustrated in Figs. 1 to 5, there are provided a pair of side bars 9 which as shown may be of angle bar construction provided with outer vertical flanges and inner facing horizontal flanges. Upwardly projecting ears are provided at both the forward and rear ends of the vertical flanges of the side bars 9 and mounted in the rear ears are pivot studs II]. A pair of back bars II are provided and these back bars preferably have loops at their lower ends encircling the pivot studs I 0 so that the bars may be swung forwardly and rearwardly on the pivot studs relative to the side bars 9. Preferably the back bars immediately above their loops are rearwardly offset somewhat so that the upper portions of the back bars fall in lines forwardly spaced from these offset portions. The upper ends of the back bars II are provided with reversely bent portions I I a. Immediately above the offset portions of the back bars, small angular brackets l2 are attached to the back bars and these brackets carry pivot studs I2a.

A pair of toggle links I3 and I 4 respectively, are pivotally connected by pivots I5 to the rear sides of the offset portion of the back bars [I near the lower ends of the bars and these toggle links have outer angular portions to carry the main portions of the bars as low as possible when the toggle links are extended. The toggle links I3 and I4 are provided with downwardly extending cars at their inner ends connected together by a pivot I6 and the said ears are somewhat oifset from the main portions of the toggle links so that when the two toggle links are extended, as best shown in Fig. 3, the inner ends of the links will abut each other. Two pairs of toggle links I'Iand I8 are provided and the links I? are connected by pivots I9 to the rear sides of the back bars II in spaced relation above the lower ends of these bars, while the links I8 are connected by pivots 20 to the toggle links I3 and I 4 respectively, in inwardly spaced relation from the outer ends of these links. The toggle links I! and I 8 are connected at their inner ends by pivots 2| in the same manner as are the links H and I4 by the pivot l6. Pivots I9, 20, and 2| are so located relative to the pivots I 5 and the pivots I6 that the three sets of toggles may be fully extended slightly past dead center relation with the various links of these toggles in straight line relation when the back bars I I are disposed in parallel relation, as best shown in Fig. 3.

A strip 22 of flexible material such as canvass, runs between and is applied to the two back bars I I near t e upp portions thereof and this strip preferably is provided with open ended pockets 22a at its ends within which the upper portions of the back bars II above the angular brackets I2 are received. The reversely bent portions Ila are rearwardly disposed from the pockets 22a and prevent the strip from slipping oil the back bars II.

Connected by outwardly extending pivot studs 23 mounted in the forward ears of the vertical flanges of the side bars 9 are clamping members 24. These clamping members are of peculiar shape for effective clamping action on seats such as the seats A and B of different thicknesses. Clamping members 24, as viewed in Figs. 1 and 2, project downwardly for a short distance below the pivots 23, whereupon they incline downwardly and rearwardly to form inclined surfaces 2411 at the upper edges of their lower portions and they are provided with upwardly projecting prongs 24b at their rear ends. Clamping bars 25 are connected by pivots 26 slightly below the level of the pivots 23 to the clamping members 24. The portions of clamping bars 25 immediately adjacent the pivots 23 are laterally offset to other portions of the bars 25 to permit limited relative swinging movement of the clamping bars 25 relative to the clamping members 24 and at the same time to form end abutments 25b above pivots 26 as best shown in Figs. l, 2, 4 and 5. The abutments 25b are adapted to engage end abutments 240 formed on the clamping members 24 above pivots 26 to limit the swinging movement between the clamping bars 25 and the clamping members 24. The clamping bars 25 extend rearwardly from the pivots 26 and near their rear ends the clamping bars are provided with longitudinal slots 25a having several diagonally upwardly and rearwardly inclined extensions. Forked tubes 21 receive the rear portions of the clamping bars 25 between the forked portions thereof and the forward ends of the forked portions carry pivot studs 28 which extend through the slots 25a. Cables 29 or equivalent flexible members such, for example, as chains are connected to the forked tubes 21 and two tubular eyes 30 which, in turn, are connected for pivotal movement to the pivot studs l2a.

There is preferably provided a pneumatic cushion 31 which will fit between the two side bars 9 when the back rest is extended and this cushion may, if desired, be releasably attached in any suitable manner, not illustrated, to the side bars 9. In order to prevent the various parts pivoted together from striking each other, friction spacing washers 32 are preferably provided between various relative moving parts at the various pivot joints.

Assuming that the back rest is in collapsed condition shown in Figs. 4 and 5, to place the back rest in extended position, it is merely necessary to draw the two back bars ll apart and swing the toggle links l3 and i4 downwardly to the position shown in Fig. 3. The back bars Il may then be swung upwardly relative to the side bars 9, whereupon the back rest is in position to be applied to a seat, such, for example, as the seat A shown in Fig. l. The clamping members 24 are, of course, swung downwardly and the side bars 9 are pushed back on the seat A as far as possible. If the seat happens to be quite thin as the seat A, the inclined surfaces 24a of clamping members 24 will be brought into engagement with the lower forward edge of the seat and the prongs 241) will not engage the seat. If the cushion 3| is to be used, it may be applied between the two side bars 9, whereupon the back rest is ready for use. As a person sits down on the seat and leans back against the flexible strip 22, the braces formed by the cables 29, forked tubes 21 and tubular eyes 30 will tighten and these braces will tend to swing the clamping bars 25 upwardly carrying the clamping bars into abutment with the clamping members 24. This will tend to swing the lower portions of the clamping members 24 upwardly thereby bringing the surfaces 24a into tightly clamping engagement with the lower forward edge of the seat A. If through the clamping action of the clamping members 24, the surfaces 24a of these clamping members dig into the lower forward edge of the seat A, the clamping members will swing upwardly until the prongs 24b engage the bottom of the seat so that the back rest cannot be released while in use. In Fig. 2, the manner of engagement of the clamping members with the thicker seat B is illustrated. When the back rest is applied to a comparatively thick seat, such as the seat B, the prongs 24b will engage the bottom of the seat and the clamping action will take place between the side bars 9 and the prongs 24b chiefly.

If it is desired to adjust the inclination of the back of the back rest, this can be readily accomplished by slipping the pivot studs 28 carried by the forked tubes 21 downwardly from the extensions in which they are placed in the slots 25a, whereupon the pivot studs may be moved into other extensions. The braces formed by the cables 29, forked tubes 21 and the tubular eyes 30 will then extend further forwardly or rearwardly from the clamping bars 25, so that the back of the back rest will take a different inclination as the seat equipped with the back rest is occupied.

To fold the back rest up into collapsed condition, the back rest is slid forwardly on the seat to release the clamping members 24, whereupon the clamping members 24 are swung upwardly relative to the side bars 9, the back bars II are swung downwardly against the side bars 9 and the clamping bars 25 are swung downwardly adjacent the side bars 9. The various toggles formed by the links l3 and I4 and I1 and 18 are then collapsed, whereupon the back rest will take the position shown in Figs. 4 and 5. The back rest in collapsed condition will take up but small compass and can be readily inserted into a bag or the like. If the cushion 3| that is used is a pneumatic cushion, the air from the cushion may be exhausted as the back rest is collapsed and the cushion may be folded up with the back rest.

Referring now to the embodiment of. the invention illustrated in Figs. 6, '1 and 8, there is provided a back rest particularly adapted for use on seats of such thickness or of such construction that clamping members such as the clamping members 24 in the previously described construction, cannot engage beneath the seat. The embodiment illustrated in Figs. 6, '1 and 8 includes side bars 33 preferably of channel-shape as illustrated, and having downturned forked forward ends 33a provided with corrugations on their rear surfaces. Pivot studs 34 are supported in the upper parts of. the forked portions 33 and mounted on these pivot studs 33 are angularshaped clamping members 35 having lower portions provided with corrugated gripping surfaces 35a which lower parts are received between the forked portions 33 of the side bars 33a. The rear ends of the clamping members 35 are provided with slots 351) similar to the slots 25a of the previously described construction and pivot studs 33 carried by forked tubes 31 to which cables 38 are attached, are received within the slots 35b. The back of the back rest illustrated in Figs. 6, '1, and 8 is constructed very similar to the back of the previously described construction and includes back bars 39 and toggles 40 and 41 corresponding to the toggles of the first described construction. Attached in the same fashion to the back bars 39 is a flexible strip 42 corresponding to the strip 22. The rear ends of the side bars 33 are forked and carry pivots 43 which receive eye-like portions 39a formed near the lower ends of the back bars 39. The back bars 39 unlike the bars II have rearwardly extending projections 3% which run downwardly from the eye-like portion 39a and are arcuately curved and provided with teeth 390 on the lower sides of their arcuately curved portions. These extensions are also provided with downwardly extending prongs 39d at their rear ends. Cables 38 are connected to eyes 44 and these eyes are mounted for swinging movement on pivot studs 45 carried by brackets 46 secured to back bars 39.

The embodiment illustrated in Figs. 6, 7 and 8 is collapsed and extended much in the same manner as is the first described embodiment and it is applied to a seat such as the concrete seat C illustrated in much the same manner. The side bars 33 are pushed back as far as possible on the seat so as to bring the corrugated downwardly extending portions 33a of the bars into engagement with the front of the seat C. Then as a person occupies the seat and puts his pressure against the back of the back rest, the angularshaped clamping members 35 will be swung upwardly to carry the corrugated portions 35a into a gripping engagement with the front of the seat. The teeth 390 of the rearward extensions 39?) of the back bars 39 will grip the top of the seat C tightly and there is enough spring in these extensions 3% that the prongs 3903 will be brought into engagement with the top of the seat. The extensions 3% cooperating with the clamping members 35 will maintain the back rest in position without slipping on the seat.

It will be seen that a back rest of cheap and simple construction has been provided which can be extended and collapsed with a minimum of effort, can be stowed away in small compass and which when extended and applied to a seat will hold its position. Also the back rest is adapted for use on seats of various thicknesses. It is particularly contemplated that the back rest will be used on the seats of row boats, stadiums, grandstands and the like, although of course, the back rest may be put to many other different uses.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of the present invention, which, generally stated, consists in the matter shown and described and set forth in the appended claims.

What is claimed is:-

1. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected respectively to the rear ends of said side bars for forward swinging movement, extensible means interconnecting said back bars, clamps pivotally connected to forward portions of said side bars and folding braces attached to said clamps and to said back bars above said first mentioned pivots, said braces urging said clamps into clamping relation with the seat as pressure is applied against said back bars.

2. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected respectively to rear portions of said side bars for forward swinging movement, extensible means interconnecting said back bars, clamps pivotally connected to the forward portions of said side bars and having downwardly extending portions projecting below said side bars to engage a seat, folding braces running from the rear portions of. said clamps to said back bars above the pivots connecting said back bars to said side bars, said folding braces urging said clamps to swing on their pivots into tightly clamping relation as pressure is applied against said back bars.

3. A folding back rest for a seat, comprising a pair of back bars, extensible means interconnecting the same, a pair of side bars pivotally connected to the lower ends of said back bars for swinging movement against said back bars, clamps pivotally connected to forward portions of said side bars and having downwardly projecting portions for engagement with a seat, said clamps having rearward projections above said side bars and folding braces connected to said rearward projections of said clamps and also to said back bars above the pivots connecting said back bars to said side bars, said braces urging the downwardly extending portions of said clamps into clamping engagement with a seat as pressure is applied against said back bars.

4. In a folding back rest for a seat, a pair of side bars adapted to rest on the seat, a pair of back bars pivotally connected respectively to said side bars for forward swinging movement, the lower portions of said back bars being offset rearwardly relative to the upper portions thereof, toggles interconnecting the lower portions of said back bars, a flexible strip running between and connecting the upper portions of said back bars and means for bracing said back bars and for attaching said side bars to the seat.

5. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected to the rear portions of said side bars for forward swinging movement, extensible means interconnecting said back bars, hookshaped clamping members pivotally connected to forward portions of said side bars and projecting below the same, said clamping members having upwardly projecting prongs at their rear ends and having diagonally inclined upper surfaces below their pivots and collapsible braces interconnecting said clamping members with said back bars, said braces being attached to said back bars above the pivots connecting said side bars to said back bars.

6. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected respectively to rear portions of said side bars for forward swinging movement, extensible means interconnecting said back bars, hook-shaped clamping members pivotally connected to forward portions of said side bars, clamping bars pivotally connected to said clamping members below the pivots connecting said clamping members to said side bars, said clamping bars having abutments adapted to strike said clamping members as said clamping bars are upwardly swung and collapsible braces connecting the rear portions of said clamping bars to said back bars above the pivots connecting said back bars to said side bars.

7. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected respectively to rear portions of said side bars for forward swinging movement, said back bars having rearward extensions below said pivots for engagement with the seat, extensible means interconnecting said back bars, angular clamps pivotally connected to forward portions of said side bars, said clamps having downwardly extending projections adapted to bear against the forward side of a seat, and having rearwardly extending projections above said side bars, and braces interconnecting the rearwardly extending projections of said angular clamps with said back bars above said first mentioned pivots.

8. A folding back rest for a seat, comprising a pair of side bars, a pair of back bars pivotally connected respectively to the rear ends of said side bars for forward swinging movement, means interconnecting said back bars, clamps pivotally connected to forward portions of said side bars and folding braces attached to said clamps and to said back bars above said first mentioned pivots, said braces urging said clamps into clamping relation with the seat as pressure is applied against said back bars.

9. The structure defined in claim 8, said folding braces and clamps including adjustable interlocking members.

10. A folding back rest for a seat, comprising a pair of side bars adapted to rest on the seat, a pair of back bars pivotally connected respectively to said side bars for forward swinging movement, the lower portions of said back bars being offset rearwardly relative to the upper portions thereof, collapsible means interconnecting the lower portions of said back bars, a collapsible member interconnecting the upper portions of said back bars, and collapsible means for holding said back bars in upwardly extending relation from said side bars and for attaching said side bars to the seat.

ANTHONY M. SCHOENHOFF. 

